Substantial strides toward the achievement of the research objectives of the original grant proposal have been made. Nevertheless, the research objectives of this renewal application remain essentially unchanged. The three main goals of the project, in abbreviated form, are as follows: 1. To study psychoacoustic functions via the hearing impaired population with view of contributing to understanding of basic auditory processes and the theory of hearing. 2. To improve techniques for diagnosis among pathologies and lesions within the auditory complex. 3. To describe more fully the role of the central nervous system in the subtleties of auditory experience. The very breadth and complexity of these goals testifies to the fact that substantial progress toward their attainment can be made while leaving important horizons almost totally unexplored. To give information to some of these unexplored areas is the goal of the research proposed herein.